hadd.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
 
 
//
// includes
//
 
#include <RootCoreUtils/hadd.h>
 
#include <sstream>
#include <TFileMerger.h>
#include <TList.h>
#include <TSystem.h>
#include <RootCoreUtils/Assert.h>
#include <RootCoreUtils/PrintMsg.h>
#include <filesystem>
 
//
// method implementations
//
 
namespace RCU
{
  void hadd (const std::string& output_file,
         const std::vector<std::string>& input_files,
         unsigned max_files)
  {
    if (input_files.size() == 1)
    {
      // if there is only one input file, create a symlink instead of merging
      std::filesystem::create_symlink (input_files.front(), output_file);
      return;
    }
 
    TFileMerger merger (false, false);
 
    merger.SetMsgPrefix ("rcu_hadd");
    merger.SetPrintLevel (98);
 
    if (max_files > 0)
    {
      merger.SetMaxOpenedFiles (max_files);
    }
 
    if (!merger.OutputFile (output_file.c_str(), false, 1) )
    {
      RCU_THROW_MSG ("error opening target file: " + output_file);
    }
 
    for (std::vector<std::string>::const_iterator input = input_files.begin(),
       end = input_files.end(); input != end; ++ input)
    {
      if (!merger.AddFile (input->c_str()))
      {
    RCU_THROW_MSG ("error adding input file: " + *input);
      }         
    }
    merger.SetNotrees (false);
 
    bool status = merger.Merge();
 
    if (status)
    {
      std::ostringstream msg;
      msg << "merged " << merger.GetMergeList()->GetEntries()
      << " input files into " << output_file;
      RCU_PRINT_MSG (msg.str());
    } else
    {
      RCU_THROW_MSG ("hadd failure during the merge");
    }
  }
}